Bill Skarsgård haunts a new part of Maine in official Castle Rock trailer

Yes, that’s Bill Skarsgård, and yes, he’s prowling through one of Stephen King’s fictional Maine towns, but he’s not playing Pennywise, and this isn’t Derry.

This is Castle Rock, and he’s playing a man everyone wants to know more about. In the official trailer for Hulu’s anthology series based on King’s works, Skarsgård’s unnamed Shawshank prisoner is not only the catalyst for the drama’s dark plot, but also a walking mystery. Those working at Shawshank have no idea who he is or where he comes from, and more importantly, are clueless as to who locked him up in a cage underground.

Making the riddle of his identity all the more difficult is his silence — until he meets death-row attorney Henry Deaver (André Holland) and has questions of his own. “Has it begun?” he asks Henry in the trailer. “Do you hear it now? You have no idea what’s happening here, do you?”

He’ll know soon enough. The teaser offers glimpses at several tantalizing, disturbing scenes to come, including blood draining from a tub, masked people gathered in a dusty room, and a man with a face covered in bandages, along with King universe Easter eggs (hello, Juniper Hill!) and shots of Scott Glenn as Alan Pangborn, Sissy Spacek as Henry’s adoptive mother, and Melanie Lynskey as another Castle Rock denizen, Molly Strand. Everyone looks spooked — with good reason. “People say every inch of this town is stained with someone’s sin,” says Terry O’Quinn’s Dale Lacy in a voiceover. Sure seems like it.

CastleRock, created by Sam Shaw and Dustin Thomason (Manhattan) and executive-produced by King and J.J. Abrams, premieres July 25 on Hulu.